Substrate processing apparatus and method

ABSTRACT

In the vicinity of a rim portion of a spin base  5 , a plurality of supports  7  which abut on a bottom rim portion of a substrate W and support the substrate W are formed projecting toward above from the spin base  5 . The substrate W is supported horizontally by the plurality of supports  7 , with a predetermined distance ensured from the spin base  5  which opposes the bottom surface of the substrate W. Into the space which is created between the top surface of the substrate W and an opposing surface  9   a  of an atmosphere blocker plate  9 , inert gas is ejected from a plurality of gas ejection outlets  9   b  which are formed in the opposing surface  9   a . The inert gas thus supplied to the top surface of the substrate W presses the substrate W against the supports  7  and the substrate W is held at the spin base  5.

CROSS REFERENCE TO RELATED APPLICATION

The disclosure of Japanese Patent Applications enumerated belowincluding specification, drawings and claims is incorporated herein byreference in its entirety:

-   -   No. 2004-175730 filed Jun. 14, 2004; and    -   No. 2004-362178 filed Dec. 15, 2004.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a substrate processing apparatus which performsprocessing such as cleaning on various types of substrates such assemiconductor wafers, glass substrates for photomask, glass substratesfor liquid crystal display, glass substrates for plasma display andoptical disk substrates by supplying a processing liquid to thesesubstrates.

2. Description of the Related Art

Conventional substrate processing apparatuses of this type include asubstrate processing apparatus in which a substrate such as asemiconductor wafer is supported on a disk-shaped rotary base memberwhich is supported such that the rotary base member can freely rotateabout a vertical axis, a processing liquid such as a chemical solutionis supplied to the top and the bottom surfaces of the substrate whilerotating the substrate, and the substrate is consequently processed(Japanese Patent Application Laid-Open Gazette No. H11-176795). In thesubstrate processing apparatus described in Japanese Patent ApplicationLaid-Open Gazette No. H11-176795, a plurality of, three for instance,holding members such as chuck pins, which are disposed in the vicinityof the outer edge of the rotary base member, position and support asubstrate. This realizes transmission of rotation force from the rotarybase member to the substrate, and rotates the substrate whilerestricting the substrate in the horizontal direction. As the substraterotates while the processing liquid is supplied to the center of the topand the bottom surfaces of the substrate, the processing liquid spreadstoward outside to the substrate, and the top and the bottom surfaces ofthe substrate are accordingly processed. The processing liquid splashingat the rim of the substrate may hit and jump at an anti-splashing cup orthe like which is disposed around the rotary base member and adhereagain to the substrate. To prevent this, a blocking member is disposednear the top surface of the substrate, thereby restricting the space onthe top side of the substrate, and inert gas such as nitrogen gas isintroduced to thus restricted space. Meanwhile, similarly as for thebottom side of the substrate, inert gas is introduced to the space whichis created between the rotary base member which serves as the blockingmember and the bottom surface of the substrate, for prevention ofre-adhering of the processing liquid to the bottom surface of thesubstrate.

SUMMARY OF THE INVENTION

However, the approach that the chuck pins are disposed as a holdingmember near the outer edge of a substrate and the substrate ispositioned in the horizontal direction and supported may cause aprocessing liquid moving outward in the diameter direction on thesurface of the substrate during processing to directly hit and jump atthe chuck pins and to adhere to the surface of the substrate againwithout getting discharged to outside the substrate. In addition, as therotary base member rotates, the chuck pins disposed upward to the rotarybase member disturbs air flows around the edge surface of the substrate.In consequence, the mist-like processing liquid splashing around duringprocessing may suck in and enter the space which is created between thesubstrate and the blocking member (or the rotary base member) and adhereto the surface of the substrate again. Further, while a chuck for thesubstrate may be opened and closed (i.e., the substrate may be released)during processing for the purpose of processing a holding section on thesubstrate where the chuck pins holds the substrate, in this case, theprocessing liquid moving outward in the diameter direction over thesubstrate in particular can easily splash at the chuck pins.

The present invention has been made in light of the problems above.Accordingly, the object of the invention is to effectively preventre-adhering of a processing liquid to the surfaces of a substrate in asubstrate processing apparatus and method in which a predeterminedprocessing is performed on the substrate by supplying the processingliquid to the substrate while rotating the substrate.

According to a first aspect of the present invention, there is provideda substrate processing apparatus which performs predetermined processingby supplying a processing liquid to a substrate while rotating saidsubstrate, comprising: a rotary member which is structured to rotatefreely about a vertical axis; a rotating element which rotates saidrotary member; a support element which is disposed upward to said rotarymember and which comprises at least three supporting members which abuton a bottom surface of said substrate to thereby support said substratewith a distance from said rotary member; and a pressing element whichpresses said substrate against said supporting members by supplying gasto a top surface of said substrate and accordingly makes said rotarymember hold said substrate.

According to a second aspect of the present invention, there is provideda substrate processing method in which predetermined processing isperformed by supplying a processing liquid to a substrate while rotatingsaid substrate, said method comprising steps of: making at least threesupporting members which are disposed upward to a rotary member abut ona bottom surface of said substrate to thereby support said substratewith a distance from said rotary member; pressing said substrate againstsaid supporting members by supplying gas to a top surface of saidsubstrate and accordingly makes said rotary member hold said substrate;and rotating said rotary member about a vertical axis to therebyrotating said substrate.

The above and further objects and novel features of the invention willmore fully appear from the following detailed description when the sameis read in connection with the accompanying drawing. It is to beexpressly understood, however, that the drawing is for purpose ofillustration only and is not intended as a definition of the limits ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing which shows a first embodiment of a substrateprocessing apparatus according to the present invention.

FIG. 2 is a plan view of the spin base as it is viewed from above.

FIG. 3 is a bottom view of the atmosphere blocker plate.

FIG. 4 is a partial cross sectional view showing the structure of thesupports.

FIG. 5 is a drawing to describe a condition for holding the substrate atthe spin base.

FIG. 6 is a drawing which shows a second embodiment of the substrateprocessing apparatus according to the present invention.

FIG. 7 is a plan view of the substrate processing apparatus which isshown in FIG. 6.

FIG. 8 is a bottom view of the atmosphere blocker plate of the substrateprocessing apparatus which is shown in FIG. 6.

FIG. 9 is a flow chart of the operation of the substrate processingapparatus shown in FIG. 6.

FIG. 10 is a drawing which shows a third embodiment of the substrateprocessing apparatus according to the present invention.

FIG. 11 is a partial cross sectional view of the substrate processingapparatus shown in FIG. 10.

FIG. 12 is a flow chart of the operation of the substrate processingapparatus shown in FIG. 10.

FIGS. 13A and 13B are partial cross sectional views of a modifiedembodiment of the substrate processing apparatus shown in FIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

FIG. 1 is a drawing which shows a first embodiment of a substrateprocessing apparatus according to the present invention. This substrateprocessing apparatus is an apparatus in which a chemical solution of achemical substance, an organic solvent or the like and a rinsing liquidwhich may be pure water or DIW (hereinafter also referred to as“processing liquid(s)”) are supplied to the surfaces of a substrate Wsuch as a semiconductor wafer, and spin drying is executed afterchemical processing and rinsing of the substrate W. In this substrateprocessing apparatus, the bottom surface of the substrate W can beprocessed while supplying the processing liquid to the bottom surface ofthe substrate W, and after supplied to the bottom surface of thesubstrate W, the processing liquid moves from the bottom surface of thesubstrate W to the edge surface of the substrate W and circles over tothe top surface (a device-seating surface) of the substrate W, so thatthe top rim portion of the substrate W is processed (bevel processing).Further, when the processing liquid is supplied to the top surface ofthe substrate W, the top surface of the substrate W can be processed.

In this substrate processing apparatus, a hollow rotation shaft 1 islinked to a rotation shaft of a motor 3, and when driven by the motor 3,the rotation shaft 1 rotates about a vertical axis J. A spin base 5 islinked to and integrated with the top end of the rotation shaft 1 by afastening component such as a screw. Hence, when driven by the motor 3,the spin base 5 rotates about the vertical axis J. In the vicinity of arim portion of the spin base 5, there are a plurality of supports 7which abut on a bottom rim portion of the substrate W and support thesubstrate W, and these supports 7 are disposed projecting upward fromthe spin base 5. The substrate W is supported horizontally by thesupports 7, with a predetermined distance from the spin base 5. In thisembodiment, the spin base 5 thus corresponds to the “rotary member” ofthe present invention.

FIG. 2 is a plan view of the spin base 5 as it is viewed from above.There is an opening in a central portion of the spin base 5, and theplurality of supports 7 (twelve supports in this embodiment) aredisposed near the rim of the spin base 5. The twelve supports 7 are eachapart by 30 degrees about the vertical axis J in a radial arrangement.While at least three supports 7 are needed to support the substrate Whorizontally, considering processing of the sections where the supports7 abut on the bottom surface of the substrate W, it is desirable thatthe supports 7 are capable of freely abutting on and moving away fromthe bottom surface of the substrate W and that the supports 7 move awayfrom the bottom surface of the substrate W at least once duringprocessing. Processing of the bottom surface of the substrate Wincluding the sections where the supports 7 abut on the bottom surfaceof the substrate W necessitates at least four supports 7. If twenty foursupports 7, the double the supports 7 used in this embodiment, aredisposed, the structure will be more stable without causing any problem.The structure and an operation of the supports 7 will be described indetail later.

The substrate processing apparatus further comprises, as shown in FIG.1, an atmosphere blocker plate 9 which is disposed opposing the spinbase 5 and blocks the atmosphere above the top surface of the substrateW and a gas supplying part 21 (which corresponds to the “gas supplyingpart” of the present invention) which supplies inert gas such asnitrogen gas into the space SP which is created between the atmosphereblocker plate 9 and the top surface of the substrate W. As the gassupplying part 21 supplies the inert gas into the space SP toward thetop surface of the substrate W, the substrate W is pressed against thesupports 7 and the spin base 5 holds the substrate W. A condition forrotating the substrate W which is pressed against the supports 7 andheld at the spin base 5 will be described in detail later.

The atmosphere blocker plate 9 is attached to a bottom end of a hollowcylindrical support shaft 11 such that the atmosphere blocker plate 9can rotate with the support shaft 11 integrally. A block drive mechanism(not shown) which has a motor 9 m is linked to the support shaft 11, andtherefore, when the motor 9 m of the block drive mechanism is driven,the atmosphere blocker plate 9 together with the support shaft 11rotates about the vertical axis J which is coaxial with the rotationshaft of the spin base 5. A controller 80 controls and synchronizes themotor 9 m to the motor 3, and accordingly drives the atmosphere blockerplate 9 into rotation in the same direction and at the same rotationspeed as the spin base 5. Further, by activating an ascend/descend driveactuator (such as an air cylinder) of the block drive mechanism, thecontroller 80 moves the atmosphere blocker plate 9 closer to or awayfrom the spin base 5.

FIG. 3 is a bottom view of the atmosphere blocker plate 9. Theatmosphere blocker plate 9 is slightly larger than the diameter of thesubstrate W and has an opening at the center. The atmosphere blockerplate 9 is located above the spin base 5, and the under surface (bottomsurface) of the atmosphere blocker plate 9 is an opposing surface 9 afacing the top surface of the substrate W. There are a plurality of gasejection outlets 9 b in this opposing surface 9 a. The plurality of gasejection outlets 9 b are arranged at such positions which correspond tothe supports 7 formed on the spin base 5. To be more specific, theplurality of gas ejection outlets 9 b are arranged on a rotation trackTa of the supports 7 (FIG. 2) such that the gas ejection outlets 9 b areequidistant from each other along the circumference about the verticalaxis J. These gas ejection outlets 9 b are communicated with gasdistributing spaces 9 c respectively which are inside the atmosphereblocker plate 9. The gas ejection outlets are not necessarily limited toa plurality of openings, but instead may be a single opening such as anopening which is formed like a complete ring and concentric about thevertical axis J. However, the plurality of gas ejection outlets 9 b aremore advantageous in attaining a uniform gas ejection pressure. In thisembodiment, the atmosphere blocker plate 9 thus corresponds to the“platy member” of the present invention and the gas ejection outlets 9 bthus corresponds to the “gas ejection outlets” of the present invention.

The description is continued referring back to FIG. 1. To supply gas tothe gas distributing space 9 c which is created inside the atmosphereblocker plate 9, the gas distributing space 9 c is communicated with thegas supplying part 21 through a pipe 25. An on-off valve 23 which isopened and closed under control of the controller 80 is placed in thepipe 25. When the controller 80 opens the on-off valve 23, the inert gassuch as nitrogen gas is supplied from the gas supplying part 21 into thegas distributing space 9 c and ejected at the plurality of gas ejectionoutlets 9 b toward the top surface of the substrate W. The gas ejectionoutlets 9 b are formed in the opposing surface 9 a of the atmosphereblocker plate 9 so as to be on the rotation track Ta of the supports 7,for ejection of the inert gas approximately along the verticaldirection.

As the inert gas is ejected uniformly at the plurality of gas ejectionoutlets 9 b, the substrate W is evenly pressed against the respectivesupports 7 which are disposed projecting upward from the spin base 5.The substrate W is consequently supported horizontally at the spin base5. Since the inert gas is supplied directly to the sections in the topsurface of the substrate W where the supports 7 abut on the bottomsurface of the substrate W, it is possible to securely hold thesubstrate W at the spin base 5 in an efficient manner using the minimumnecessary amount of gas supply. The supply of the inert gas at theplurality of gas ejection outlets 9 b is not limited only to supply ontothe rotation track Ta of the supports 7, and the inert gas may besupplied toward an inner side or an outer side along the diameterdirection relative to the rotation track Ta of the supports 7.

An upper clean nozzle 12 is disposed coaxially to the opening at thecenter of the atmosphere blocker plate 9 and to the hollow section ofthe support shaft 11 so that at a nozzle outlet 12 a at the bottom endof the upper clean nozzle 12, the processing liquid such as a chemicalsolution and a rinsing liquid can be supplied to an area which is nearthe rotation center of the top surface of the substrate W which ispressed against and held at the spin base 5. The upper clean nozzle 12is connected to a pipe 13. The pipe 13 branches off at the base end. Onebranch pipe 13 a is connected to a chemical solution source 31, whilethe other branch pipe 13 b is connected to a rinsing liquid source 33.On-off valves 15 and 17 are placed respectively in the branch pipes 13 aand 13 b, making it possible to switch between supply of a chemicalsolution and supply of a rinsing liquid and thus selectively supply thechemical solution or the rinsing liquid to the top surface of thesubstrate W from the upper clean nozzle 12 as the on-off valves 15 and17 open and close under control of the controller 80.

The gap between the inner wall surface of the hollow section of thesupport shaft 11 and the outer wall surface of the upper clean nozzle 12serves as a gas supply path 18. The gas supply path 18 is communicatedwith a gas source 35 via a pipe 27 in which an on-off valve 19 isplaced. After chemical processing or rinsing using the upper cleannozzle 12, as the on-off valve 19 opens and closes under control of thecontroller 80, gas such as clean air and inert gas is supplied via thegas supply path 18 into the space SP which is created between the topsurface of the substrate W and the opposing surface 9 a of theatmosphere blocker plate 9, and the substrate W is accordingly dried.

A lower clean nozzle 41 corresponding to the “bottom-side processingliquid supplier” of the present invention is disposed coaxially to thehollow section of the rotation shaft 1, to thereby supply at a nozzleoutlet 41 a, which is at the top end of the lower clean nozzle 41, theprocessing liquid to an area which is near the rotation center of thebottom surface of the substrate W. The lower clean nozzle 41 isconnected to a pipe 43. The pipe 43 branches off at the base end. Onebranch pipe 43 a is connected to the chemical solution source 31, whilethe other branch pipe 43 b is connected to the rinsing liquid source 33.On-off valves 45 and 47 are placed respectively in the branch pipes 43 aand 43 b, making it possible to switch between supply of the chemicalsolution and supply of the rinsing liquid and thus selectively to supplythe chemical solution or the rinsing liquid to the bottom surface of thesubstrate W from the lower clean nozzle 41 as the on-off valves 45 and47 open and close under control of the controller 80.

The gap between the inner wall surface of the rotation shaft 1 and theouter wall surface of the lower clean nozzle 41 serves as a gas supplypath 48. The gas supply path 48 is communicated with the gas source 35via a pipe 51 in which an on-off valve 49 is placed, and therefore, itis possible to supply gas such as clean air and inert gas via the gassupply path 48 into the space between the bottom surface of thesubstrate W and the opposing surface of the spin base 5 as the on-offvalve 49 opens and closes under control of the controller 80.

The structure and an operation of the supports 7 will now be described.FIG. 4 is a partial cross sectional view showing the structure of thesupports. Since all the supports 7 have the identical structures, thestructure of only one support 7 will be described with reference to FIG.4. As shown in FIG. 4, a rim portion of a top surface of the spin base 5is protruded upward to form a protrusion 5 a which has a form of ahollow circular cylinder opening upward. The support 7 is disposedinside the protrusion 5 a and comprises a film member 71, a movable rod73, and a driver 75. The film member 71 has a form of a hollow circularcylinder opening downward and is made of a flexible material. The filmmember 71 is disposed inside the protrusion 5 a in such a manner thatthe outer circumference of the film member 71 is in close contact withthe inner circumference of the protrusion 5 a. The movable rod 73 isdisposed inside the film member 71 and is supported to freely move upand down to abut on and move away from the bottom surface of the topcenter of the film member 71. The driver 75 such as a motor is linked tothe movable rod 73 via a drive link section not shown and moves themovable rod 73 upward and downward. The driver 75 is not limited to amotor. Actuators in general such as air cylinders may be used instead.

In the support 7 having the above structure, as the driver 75, whenreceiving a drive signal from the controller 80, drives the movable rod73 upward via the drive link portion, the top end of the movable rod 73abuts on the bottom surface of the top center of the film member 71 andpushes up the top center of the film member 71. As this occurs, the topsurface of the film member 71 projects beyond the top end of theprotrusion 5 a of the spin base 5. Hence, with all (or at least three)of the film members 71 of the plurality of supports 7 projected in thisfashion, the substrate W is supported horizontally with a distance(which may be about 1 mm) from the top end of the protrusions 5 a of thespin base 5 while maintaining the contact between the film members 71and the bottom surface of the substrate W (FIG. 4).

On the contrary, when the driver 75 drives the movable rod 73 downward,the top end of the movable rod 73 moves away from the bottom surface ofthe top center of the film member 71, and the top surface of the filmmember 71 retracts back to the same plane as the top end of theprotrusion 5 a of the spin base 5 on its own because of its flexibility.Thus, among the projecting film members 71 of the plurality of supports7, when some except for at least three are moved down, the descendedfilm members 71 move away from the bottom surface of the substrate W. Inaddition, such film members 71 are made of resin which is flexible andanti-corrosive against the processing liquid. A fluororesin such asPCTFE (polychlorotrifluoroethylene) is preferably used as the filmmembers 71. In this embodiment, the film members 71 thus correspond tothe “supporting members” of the present invention and the driver 75 thuscorresponds to the “driver” of the present invention.

A description will now be given on the relationship between a locationof a top processing area TR, the supply positions of the inert gasejected out at the gas ejection outlets 9 b which are formed in theopposing surface 9 a of the atmosphere blocker plate 9, and thelocations of the supports 7. The top processing area TR is an area whichis processed with the processing liquid which circles over to the toprim portion of the substrate W during processing (bevel processing) ofthe top rim portion of the substrate W with the processing liquidsupplied to the bottom surface of the substrate W and circling over tothe top surface of the substrate W via the edge surface of the substrateW. Ejected substantially vertically at the gas ejection outlets 9 btoward the top surface of the substrate W, the inert gas reaches anon-processing area NTR which is on the inner side relative to the topprocessing area TR which is processed with the processing liquid whichcircles over to the top rim portion. Meanwhile, the supports 7 aredisposed in the rim portion of the spin base 5 so as to abut on andsupport the sections in the bottom surface of the substrate Wcorresponding to the non-processing area NTR to which the inert gas issupplied. This structure prevents entry of the processing liquid to thenon-processing area NTR and ensures that the processing liquid circlesover the edge surface in a uniform width along the direction of thediameter of the substrate W. As for the rim of the opposing surface 9 aof the atmosphere blocker plate 9, the opposing surface steps back asviewed from the top such that the step-back section is matched with thetop processing area TR and circling over of the processing liquid is notdisturbed.

A condition for rotating the substrate W while pressing the substrate Wagainst the supports 7 and holding the substrate W at the spin base 5will now be described with reference to FIG. 5. In the case of theapproach which requires pressing the substrate W against the supports 7which abut on the bottom surface of the substrate W, the inert gas issupplied into the space SP which is created between the top surface ofthe substrate W and the opposing surface 9 a of the atmosphere blockerplate 9, the internal pressure inside the space SP consequently rises,and the substrate W is pressed against the supports 7. In short, as thesubstrate W rotates at a high speed though there is no holding membersuch as a chuck pin which abuts on the outer edge of the substrate W andholds the substrate W, the substrate W could fly out sideways to theouter side along the diameter direction. This is because higher therotation speed of the substrate W becomes, more easily the inert gassupplied into the space SP is discharged to outside the substrate sothat the internal pressure inside the space SP becomes lower, andbecause the larger the number of revolutions of the substrate W becomes,the larger the centrifugal force which acts upon the substrate W becomes(in proportion to the square of the number of revolutions).

Hence, for the purpose of rotating the substrate W while maintaining thesubstrate W pressed against the supports 7 and held at the spin base 5,it is necessary to set a condition for the apparatus within a rangewhich satisfies the inequality below:F1<F2where the symbol F1 denotes a centrifugal force acting upon thesubstrate W and the symbol F2 denotes a friction force developingbetween the bottom surface of the substrate W and the supports 7. Whilethe centrifugal force F1 upon the substrate W acts outwardly along thediameter direction, the friction force F2 developing between the bottomsurface of the substrate W and the supports 7 acts inwardly along thediameter direction, i.e., to the opposite to the centrifugal force F1.The centrifugal force is generally expressed as mrω² (m: mass, r: theradius from the center of rotation to a mass point (m), ω: angularvelocity). Parameters associated with the apparatus which determine thecentrifugal force F1 acting upon the substrate W are the number ofrevolutions R of the spin base 5, a distance D along the diameterdirection from the vertical axis J of the spin base 5 to the physicalcenter of the substrate W (hereinafter referred to as the “amount ofeccentricity”), and the mass of the substrate W. Meanwhile, the frictionforce F2 developing between the bottom surface of the substrate W andthe supports 7 is determined by the product μN of normal force N actingupon the substrate W and a friction factor (coefficient of staticfriction) μ between the substrate W and the supports 7.

Noting this, through experiments, the inventors of the present inventionobtained the threshold values of the following five control factorsregarding the apparatus so as to satisfy the inequality above. That is,the inventors obtained the threshold values of five parameters: (1) thenumber of revolutions R of the spin base 5; (2) the amount ofeccentricity D; (3) a gas flow rate V; (4) a distance G between the topsurface of the substrate W and the opposing surface 9 a of theatmosphere blocker plate 9 (hereinafter referred to as a “gap”); and (5)the planar displacement between the substrate W and the atmosphereblocker plate 9, and the degree of parallelism between the substrate Wand the atmosphere blocker plate 9. The gas flow rate V is indicative ofthe total flow rate of the inert gas supplied to the space SP, i.e., theflow rate of the gas which is supplied to the top surface of thesubstrate W from the gas supply path 18 and the gas ejection outlets 9b. The planar displacement between the substrate W and the atmosphereblocker plate 9 is indicative of the width over which the surface of thesubstrate W and the opposing surface 9 a swing in the vertical directionas the substrate W and the atmosphere blocker plate 9 both rotate aboutthe vertical axis J. The degree of parallelism between the substrate Wand the atmosphere blocker plate 9 refers to the degree of parallelismbetween the top surface of the substrate W and the opposing surface 9 a.

In the experiments, the inventors used silicon substrates having thediameter of 300 mm, ensuring that the substrate material determining themass of the substrate W and the friction factor μ was approximatelyconstant. On the other hand, the friction factor μ is largely differentdepending upon the material of the supports 7. The friction factor μ isrelatively large when the material of the supports 7 which abut on thebottom surface of the substrate W is SiC, glassy carbon, alumina, etc.,whereas the friction factor μ is relatively small when the materialcontains a fluororesin. A fluororesin material may be PCTFE(polychlorotrifluoroethylene), PVDF (polyvinylidenefluoride), PEEK(polyetheretherketone), PVC (polyvinylchloride), etc. Meanwhile, whenKalrez (registered trademark) or perfluoroelastomer which is used for anO-ring as a chemically resistant elastic material is used, the frictionfactor μ exhibits a value between those of the group containing SiC,glassy carbon, alumina, etc and those of the group containing PCTFE,PVDF, PEEK, PVC, etc.

Calculating the threshold values of the respective parameters regardingthe apparatus using these three groups of materials, the inventorsobtained the results which are shown in Table 1 through Table 3. Table 1shows the result which was obtained when SiC, glassy carbon, alumina orthe like was used as the material of the supports 7. Table 2 shows theresult which was obtained when PCTFE, PVDF, PEEK, PVC or the like wasused as the material of the supports 7. Table 3 shows the result whichwas obtained when Kalrez (registered trademark) or perfluoroelastomerwas used as the material of the supports 7. When these ranges ofconditions shown in Table 1 through Table 3 are met, it is possible toperform stable processing without causing slipping of the substrate W onthe supports 7. TABLE 1 (1) The number of revolutions R ≦3000 (rpm) (2)The amount of eccentricity D ≦2 (mm) (3) The gas flow rate V (L/min) ≧30(4) The gap G (mm) ≦2 (5) The planar displacement ≦1 between thesubstrate and the blocker plate and the degree of parallelism betweenthe substrate and the blocker plate (mm)

TABLE 2 (1) The number of revolutions R ≦2000 (rpm) (2) The amount ofeccentricity D ≦1.5 (mm) (3) The gas flow rate V (L/min) ≧50 (4) The gapG (mm) ≦1 (5) The planar displacement ≦0.5 between the substrate and theblocker plate and the degree of parallelism between the substrate andthe blocker plate (mm)

TABLE 3 (1) The number of revolutions R ≦2500 (rpm) (2) The amount ofeccentricity D ≦1.5 to 2 (mm) (3) The gas flow rate V (L/min) ≧40 (4)The gap G (mm) ≦1.5 (5) The planar displacement ≦0.5 to 1 between thesubstrate and the blocker plate and the degree of parallelism betweenthe substrate and the blocker plate (mm)

As shown in Table 1 through Table 3, the smaller the friction factor μbetween the substrate W and the supports 7 is, the smaller the number ofrevolutions R needs be and the larger the internal pressure inside thespace SP must become by increasing the gas flow rate V and reducing thegap G This is because as the number of revolutions R increases, thecentrifugal force F1 increases, which facilitates discharging of theinert gas out from the space SP, reduces the internal pressure insidethe space SP, i.e., the normal force N acting upon the substrate W, anddecreases the friction force F2. In this embodiment, it is possible tofinely adjust the gas flow rate using a flow rate controller such as amass flow controller of course, and to finely adjust the gap between theatmosphere blocker plate 9 and the substrate W by means of pulse controlof the ascend/descend drive actuator of the block drive mechanism in theunits of 0.01 mm, and thus, the precise control of the press-holdingcondition enhances the versatility of the apparatus.

An operation of the substrate processing apparatus having the structureabove will now be described. To be more specific, processing of thebottom surface of the substrate W and the top rim portion of thesubstrate W with the processing liquid supplied to the bottom surface ofthe substrate W and circling over to the top surface of the substrate Wvia the edge surface of the substrate W will now be described. In thissubstrate processing apparatus, a substrate transportation robot notshown transports an unprocessed substrate W to the substrate processingapparatus, and as the substrate W is mounted at its back surface on thesupports 7 with the device-seating surface of the substrate W facing up,chemical processing, rinsing and drying are executed while thecontroller 80 controls the respective portions of the apparatus in themanner below. While the substrate transportation robot transports thesubstrate W, the atmosphere blocker plate 9, the support shaft 11 andthe upper clean nozzle 12 retract as one unit above the spin base 5 andstay away from the spin base 5.

Once the substrate W is mounted on the supports 7 in this manner, theatmosphere blocker plate 9, the support shaft 11 and the upper cleannozzle 12 move down as one unit, and the atmosphere blocker plate 9 isaccordingly located close to the substrate W. With the on-off valve 23open, the inert gas from the gas supplying part 21 is ejected at the gasejection outlets 9 b which are formed in the opposing surface 9 a of theatmosphere blocker plate 9 and the inert gas is supplied toward acentral portion of the top surface of the substrate W via the gas supplypath 18. This increases the internal pressure inside the space SP whichis created between the opposing surface 9 a of the atmosphere blockerplate 9 and the top surface of the substrate W, whereby the substrate Wis pressed against the supports 7 which abut on the bottom surface ofthe substrate W and held at the spin base 5. In addition, the topsurface of the substrate W is covered with the opposing surface 9 a ofthe atmosphere blocker plate 9 which has come very close to the topsurface of the substrate W. In this state, as the inert gas is ejectedevenly at the plurality of gas ejection outlets 9 b, the substrate W ispressed evenly against the supports 7 and held horizontally.

Following this, the motor 3 drives the spin base 5 and the substrate Winto rotations as one unit. The substrate W thus pressed against thesupports 7 rotates together with the spin base 5, as it is supported bythe supports 7 owing to the friction force which develops between thesupports 7 and the substrate W. At this stage, the motor 9 m of theblock drive mechanism not shown turns on, thereby rotating theatmosphere blocker plate 9 about the vertical axis J in the samedirection and at the approximately same number of revolutions as thespin base 5. This prevents the rotations from creating excessive airflows between the substrate W and the atmosphere blocker plate 9. Inthis embodiment, the motor 3 and the motor 9 m form the “rotatingelement” of the present invention.

As the substrate W starts rotating, the controller 80 opens the on-offvalve 45, and the chemical solution is supplied at the nozzle outlet 41a of the lower clean nozzle 41 to a central portion of the bottomsurface of the substrate W from the chemical solution source 31. Thechemical solution supplied to the central portion of the bottom surfaceof the substrate W spreads throughout the bottom surface due to thecentrifugal force created by the rotations of the substrate W, therebyachieving the chemical processing of the entire bottom surface of thesubstrate W. As the respective supports 7 move away at least once fromthe bottom surface of the substrate W during the chemical processing,the chemical solution circles even into those sections where thesupports 7 and the substrate W contact and these contact sections areprocessed. To this end, the twelve supports 7 may move away one at atime for example, or to the extent that at least three supports 7 remainabutting on the bottom surface of the substrate W, two or more supports7 may move away at a time. The supply of the inert gas from the gassupply path 18 opposes against the pressure of ejection of the chemicalsolution at the nozzle outlet 41 a of the lower clean nozzle 41, in thecentral portion of the bottom surface of the substrate W.

While the chemical solution moving outwardly along the diameterdirection of the substrate W via the bottom surface of the substrate Wsplashes to outside the substrate W except for the chemical solutionwhich circles onto the top surface of the substrate W, since thisembodiment does not use a holding member such as a chuck pin which holdsthe substrate W at the outer edge of the substrate W, the chemicalsolution which moves outwardly along the diameter direction of thesubstrate W will not jump back onto the surface of the substrate.Further, the absence of a factor which disturbs air flows near the outeredge of the substrate reduces blowing of the mist of the processingliquid toward the surface of the substrate. This prevents jumping backof the chemical solution onto the non-processing area NTR (a region onthe inner side relative to the top processing area TR) in the topsurface of the substrate W, and hence, corrosion of the non-processingarea NTR (which is a device area in the case of a semiconductor waferfor instance). In addition, as blowing of the mist of the processingliquid is prevented, it is possible to suppress adhering of particles tothe surface of the substrate.

A portion of the chemical solution supplied to the central portion ofthe bottom surface of the substrate W flows from the central portion tothe rim of the substrate W, and circles over the edge surface of thesubstrate W and reaches the top rim portion of the substrate W. The toprim portion of the substrate W is thus thoroughly processed as the topprocessing area TR. As described above, since this embodiment does notuse a holding member such as a chuck pin which holds the substrate W atthe outer edge of the substrate W, the amount of the circling processingliquid does not become nonuniform. Hence, uneven processing whichresults from holding the substrate W at the outer edge of the substrateW is prevented.

After the chemical processing for a predetermined period of time, whilethe substrate W and the atmosphere blocker plate 9 still rotate, thecontroller 80 closes the on-off valve 45 and the supply of the chemicalsolution from the chemical solution source 31 is accordingly stopped,and the on-off valve 47 is then opened. As a result, the rinsing liquid(such as pure water, DIW and the like) is supplied to the centralportion of the bottom surface of the substrate W at the nozzle outlet 41a of the lower clean nozzle 41. In this state, rinsing is performed inwhich the rinsing liquid supplied to the central portion of the bottomsurface of the substrate W spreads throughout the bottom surface of thesubstrate W and washes away the chemical solution adhering to thesubstrate W. Further, the rinsing liquid supplied to the central portionof the bottom surface of the substrate W circles over the edge surfaceof the substrate W and washes away all of the chemical solution adheringto the top processing area TR of the substrate W. The chemical solutionwhich exist in the bottom surface, the edge surface and the top rimportion of the substrate W after the chemical processing is washed awayin this manner.

After rinsing for a predetermined period of time, the controller 80closes the on-off valve 47 and the rinsing completes. Next, thecontroller 80 rotates the motor 3 and the motor 9 m of the block drivemechanism at a high speed, so that the substrate W and the atmosphereblocker plate 9 accelerate their rotations and the liquid componentsadhering to the surfaces of the substrate W and the atmosphere blockerplate 9 are drained off owing to the centrifugal force. During thisdrying, in addition to the supply of the inert gas into the space SPwhich is created between the top surface of the substrate W and theopposing surface 9 a of the atmosphere blocker plate 9, the controller80 opens the on-off valve 49, thereby introducing the inert gas into thespace between the bottom surface of the substrate W and the opposingsurface of the spin base 5 at a predetermined flow rate from the gassupply path 48. In consequence, the space around the substrate W isquickly substituted with the inert gas, which prevents contamination ofthe substrate W with the chemical atmosphere which remains in the space.Further, unwanted oxide films will not grow on the top and the bottomsurfaces of the substrate W.

After the drying, the controller 80 stops the motor 3, thereby stoppingthe rotations of the substrate W, and stops the motor 9 m of the blockdrive mechanism, thereby stopping the rotations of the atmosphereblocker plate 9. The on-off valves 19 and 23 are thereafter closed andthe supply of the gas into the space SP is stopped, and the substrate Wis released from pressing and holding. The atmosphere blocker plate 9then moves toward above, and the substrate transportation robot unloadsthe processed substrate W.

As described above, in this embodiment, the substrate W is supportedwith a distance from the spin base 5 by the supports 7 which abut on thebottom surface of the substrate W, and the inert gas supplied to the topsurface of the substrate W presses the substrate W against the supports7 and the substrate W is held at the spin base 5. Owing to the frictionforce which develops between the supports 7 and the substrate W, thesubstrate W as it is supported by the supports 7 rotates together withthe spin base 5. As the substrate W is held in this manner, it is notnecessary to use a holding member such as a chuck pin which contacts theouter circumferential edge of the substrate W and holds the substrate W.Hence, the processing liquid which moves outward in the diameterdirection on the surface of the substrate W as the substrate W rotatescan never directly contact a holding member such as a chuck pin and jumpback onto the surface of the substrate. Further, the absence of a factorwhich disturbs air flows near the outer edge of the substrate reducessucking in of the mist-like processing liquid toward the surface of thesubstrate. This effectively prevents re-adhering of the processingliquid to the surface of the substrate.

In addition, since the supports 7 abut on and support the bottom surfaceof the substrate W and the substrate is held as the inert gas issupplied to the top surface of the substrate W, it is possible to ensurethat the processing liquid circles over to the top rim portion (topprocessing area) TR of the substrate W in a uniform amount, withoutdisturbing the circling of the processing liquid over to the top rimportion TR of the substrate W. Further, since the inert gas is suppliedto the non-processing area NTR of the substrate W which is located onthe inner side relative to the top processing area TR of the substrateW, entry of the chemical solution to the non-processing area NTR isprevented, ensuring that the processing liquid circles from the edgesurface over a uniform width along the direction of the diameter of thesubstrate W.

Further, since the supports 7 can abut on and move away from the bottomsurface of the substrate W and each support 7 moves away from the bottomsurface of the substrate W at least once during processing whilesupplying the processing liquid to the bottom surface of the substrateW, the processing liquid circles even onto the sections where thesupports 7 abut on the bottom surface of the substrate W and the entirebottom surface of the substrate W is processed.

Second Embodiment

FIG. 6 is a drawing which shows a second embodiment of the substrateprocessing apparatus according to the present invention. FIG. 7 is aplan view of the substrate processing apparatus which is shown in FIG.6. A major difference of the second embodiment from the first embodimentis that a processing liquid nozzle 6 is additionally disposed at whichthe processing liquid is supplied to the top rim portion of thesubstrate W and that because of the processing liquid nozzle 6 which isadditionally disposed, the structure of the atmosphere blocker plate 90is modified partially. The second embodiment is otherwise basicallysimilar in structure to the first embodiment. Hence, as for a conditionfor rotating the substrate W while pressing the substrate W against thesupports 7 and holding the substrate W at the spin base 5, when theparameter range described in relation to the first embodiment are met,stable processing is realized without causing slipping of the substrateW. In the following, the same structures will be denoted at the samereference symbols but will not be described, and the characteristics ofthe second embodiment will be described with a primary focus ondifferences.

In this embodiment, the top rim portion of the substrate W is processedwith the processing liquid which is supplied at the processing liquidnozzle 6 which is disposed facing the top surface of the substrate W,not with the processing liquid which circles over to the top surface ofthe substrate W via the edge surface of the substrate W after suppliedto the bottom surface of the substrate W. Disposed to the atmosphereblocker plate 9 above the spin base 5, the processing liquid nozzle 6 iscapable of supplying the processing liquid to the top rim portion of thesubstrate W. That is, a chemical solution pipe 61 and a rinsing liquidpipe 63 are disposed to the inside of the processing liquid nozzle 6 sothat a chemical solution and a rinsing liquid can be supplied from thebottom ends of the respective pipes 61 and 63 to the top rim portion ofthe substrate W. The chemical solution pipe 61 is connected with thechemical solution source 31 via a pipe 14, while the rinsing liquid pipe63 is connected with the rinsing liquid source 33 via a pipe 22. On-offvalves 16 and 20 are placed respectively in the pipes 14 and 22, andtherefore, as the controller 80 controls the on-off valves 16 and 20,the flow rates of the chemical solution and the rinsing liquid fed tothe processing liquid nozzle 6 are adjusted.

The processing liquid nozzle 6 is fixed to the top end of one arm 65(FIG. 7). On the other hand, a nozzle move mechanism 67 is linked withthe base end of the arm 65. As the nozzle move mechanism 67 is activatedin response to a control command from the controller 80, the arm 65pivots about the core of rotations P. Hence, the processing liquidnozzle 6 is capable of moving between an opposed position (the positiondenoted at the solid line in FIG. 7) which is opposed against thesubstrate W and at which the processing liquid is supplied to the toprim portion of the substrate W and a retract position (the positiondenoted at the broken line in FIG. 7) which is off to the side from asupply position. In this embodiment, the processing liquid nozzle 6 thuscorresponds to the “top-side processing liquid supplier” of the presentinvention.

FIG. 8 is a bottom view of the atmosphere blocker plate 90 of thesubstrate processing apparatus which is shown in FIG. 6. A difference ofthe atmosphere blocker plate 90 from the atmosphere blocker plate 9 ofthe substrate processing apparatus according to the first embodiment isthat the atmosphere blocker plate 90 comprises a dent 90 a which is alocal recess in the brim of the atmosphere blocker plate 90 toward thecenter and that the gas ejection outlets 90 b which are around the dent90 a are formed inclined downward and outward so that the inert gas isejected downward and outward to the top surface of the substrate W. Thispermits the processing liquid nozzle 6 slip into the dent 90 a and getlocated at an opposed position facing the top rim portion (topprocessing area) TR of the substrate W. So as to cover the top surfaceof the substrate W over a wide range with the atmosphere blocker plate90, the dent 90 a and the processing liquid nozzle 6 have minimumnecessary sizes which are necessary to supply the processing liquid tothe top rim portion TR of the substrate W. Further, ejection of theinert gas downward and outward at the gas ejection outlets 90 b preventsthe processing liquid from entering the non-processing area NTR (aregion on the inner side relative to the top processing area TR) in thetop surface of the substrate W when the processing liquid nozzle 6 is atthe opposed position, and hence, the chemical atmosphere from enteringthe space SP which is created between the top surface of the substrate Wand the atmosphere blocker plate 90 when the processing liquid nozzle 6is at the retract position. The other structure is basically the same asthat of the atmosphere blocker plate 9 of the substrate processingapparatus according to the first embodiment, and therefore, will not bedescribed.

An operation of the substrate processing apparatus having the structureabove will now be described with reference to FIG. 9. FIG. 9 is a flowchart of the operation of the substrate processing apparatus shown inFIG. 6. First, a substrate transportation robot not shown transports anunprocessed substrate W to the substrate processing apparatus, and asthe substrate W is mounted at its back surface on the supports 7 withthe device-seating surface of the substrate W facing up, the controller80 moves down the atmosphere blocker plate 90 and the atmosphere blockerplate 90 is accordingly located close to the substrate W (Step S1). Withthe on-off valve 23 open, the inert gas from the gas supplying part 21is ejected at the gas ejection outlets 9 b and 90 b which are formed inthe opposing surface 9 a of the atmosphere blocker plate 90 and theinert gas is supplied toward a central portion of the top surface of thesubstrate W via the gas supply path 18, whereby the substrate W ispressed against the supports 7 and held at the spin base 5 (Step S2).

Next, the controller 80 activates the nozzle move mechanism 67 and theprocessing liquid nozzle 6 accordingly is positioned at the opposedposition (Step S3). Following this, the controller 80 drives the motor 3while maintaining the atmosphere blocker plate 90 in a halt, so that thesubstrate W rotates together with the spin base 5 (Step S4). The on-offvalve 16 is then opened, supplying the chemical solution to the top rimportion TR of the substrate W from the processing liquid nozzle 6 (StepS5). In consequence, the chemical solution is uniformly supplied to theentire top rim portion TR of the substrate W over a predetermined widthfrom the end of the substrate W, attaining the chemical processing ofthe top rim portion TR of the substrate W. After the chemicalprocessing, the controller 80 opens the on-off valve 20 and the rinsingliquid is supplied to the top rim portion TR of the substrate W from theprocessing liquid nozzle 6 (Step S6). The rinsing liquid thus washesaway the chemical solution adhering to the top rim portion TR of thesubstrate W.

As the chemical processing and rinsing of the top rim portion TR of thesubstrate W thus complete, the controller 80 activates the nozzle movemechanism 67 and the processing liquid nozzle 6 is positioned at theretract position (Step S7). While this is followed by processing of thebottom surface of the substrate W, it is preferable that the controller80 at this stage drives the motor 9 m of the block drive mechanism andthe atmosphere blocker plate 90 rotates in the same direction and atapproximately the same number of revolutions as the spin base 5 (StepS8). This prevents the rotations from creating excessive air flowsbetween the substrate W and the atmosphere blocker plate 90, andprevents the chemical atmosphere from sucking in and the chemicalsolution from jumping back.

The controller 80 then opens the on-off valve 45, whereby the chemicalsolution is supplied at the nozzle outlet 41 a of the lower clean nozzle41 toward a central portion of the bottom surface of the substrate Wfrom the chemical solution source 31 (Step S9). Therefore, due to thecentrifugal force which is created as the substrate W rotates, thechemical solution supplied to the central portion of the bottom surfaceof the substrate W spreads throughout the bottom surface of thesubstrate W, achieving the chemical processing of the entire bottomsurface of the substrate W. The chemical processing of the bottomsurface of the substrate W may be performed during the chemicalprocessing of the top rim portion TR of the substrate W or may bepartially overlapped with the chemical processing of the top rim portionTR of the substrate W. After the chemical processing for a predeterminedperiod of time, while the substrate W still rotates, the controller 80closes the on-off valve 45, so that the supply of the chemical solutionfrom the chemical solution source 31 is accordingly stopped and thechemical solution is drained off and discharged to outside thesubstrate.

As the chemical solution is thus drained off, the controller 80 opensthe on-off valve 47 for rinsing of the bottom surface of the substrate W(Step S10). The rinsing of the bottom surface of the substrate W as wellmay be performed during rinsing of the top rim portion TR of thesubstrate W or may be partially overlapped with rinsing of the top rimportion TR of the substrate W. After the rinsing for a predeterminedperiod of time, the controller 80 closes the on-off valve 47, so thatthe supply of the rinsing liquid is stopped and the rinsing liquid isdrained off and discharged to outside the substrate.

Next, while the inert gas is supplied into the space SP which is createdbetween the top surface of the substrate W and the opposing surface 9 aof the atmosphere blocker plate 90, the controller 80 opens the on-offvalve 49, thereby introducing the inert gas into the space between thebottom surface of the substrate W and the opposing surface of the spinbase 5 at a predetermined flow rate from the gas supply path 48. Themotor 3 and the motor 9 m then rotate at a high speed, whereby theresidual rinsing liquid is spun off and the substrate is dried (StepS11).

As the drying of the substrate W ends, the controller 80 controls themotor 9 m, thereby stopping the rotations of the atmosphere blockerplate 90 (Step S12), and the controller 80 controls the motor 3, therebystopping the rotations of the substrate W (Step S13). The on-off valves19 and 23 are thereafter closed, the supply of the gas into the space SPis stopped, and the substrate W is accordingly released from pressingand holding (Step S14). The atmosphere blocker plate 90 then movestoward above, and the substrate transportation robot unloads theprocessed substrate W. This completes the series of chemical processingand rinsing.

As described above, this embodiment does not need a holding member suchas a chuck pin which contacts the outer edge of the substrate W andholds the substrate W, and therefore, effectively prevents re-adheringof the processing liquid to the surfaces of the substrate as in the caseof the first embodiment. Further, since the processing liquid issupplied from the processing liquid nozzle 6 directly to the top rimportion (top processing area) TR of the substrate W, the followingadvantages are obtained. That is, as compared with processing of the toprim portion TR of the substrate W with the processing liquid supplied tothe bottom surface of the substrate W and circling from the edge surfaceof the substrate W, it is easier to control the processing width fromthe edge surface along the diameter direction of the substrate W. Hence,it is possible to control the processing width from the edge surfacealong the diameter direction of the substrate W freely and at a highaccuracy. Even when the substrate W such as a semiconductor wafer has anotch therefore, it is possible to ensure the uniformity of theprocessing width in the notch.

In this embodiment as well, each support 7 moves away from the bottomsurface of the substrate W at least once during processing whilesupplying the processing liquid to the bottom surface of the substrateW, the processing liquid circles over even to the sections where thesupports 7 abut on the bottom surface of the substrate W and the entirebottom surface of the substrate W is processed.

Further, while the chemical solution and the rinsing liquid are suppliedat the processing liquid nozzle 6 to the substrate W in this embodiment,different nozzles may be disposed respectively for the chemical solutionand the rinsing liquid. Even in this case, the sizes of the nozzles maybe the same and the nozzles may be alternately disposed to the side ofthe atmosphere blocker plate 90, so that the atmosphere blocker plate 90is formed with a dent 90 a provided in one place.

Third Embodiment

FIG. 10 is a drawing which shows a third embodiment of the substrateprocessing apparatus according to the present invention. FIG. 11 is apartial cross sectional view of the substrate processing apparatus shownin FIG. 10. While being similar to the second embodiment in that theprocessing liquid nozzle is additionally disposed at which theprocessing liquid is supplied to the top rim portion of the substrate W,the third embodiment is different from the second embodiment in that theatmosphere blocker plate 90 can not rotate while the processing liquidis supplied to the top surface of the substrate W in the secondembodiment, the atmosphere blocker plate can rotate in the thirdembodiment. Except for this difference which requires a partialmodification of the structure of the atmosphere blocker plate, thestructure according to the third embodiment is basically similar tothose according to the first and the second embodiments. Hence, as for acondition for rotating the substrate W while pressing the substrate Wagainst the supports 7 and holding the substrate W at the spin base 5,when the parameter range described in relation to the first embodimentare met, stable processing is realized without causing slipping of thesubstrate W. In the following, the same structures will be denoted atthe same reference symbols but will not be described, and thecharacteristics of the third embodiment will be described with a primaryfocus on differences.

In the third embodiment, the atmosphere blocker plate 91 comprises anopposing surface 91 a which is circular and smaller than the plan sizeof the substrate W. Hence, when the opposing surface 91 a is facedparallel against the top surface of the substrate W, the top rim portionof the substrate W is exposed without getting covered with the opposingsurface 91 a. The atmosphere blocker plate 91 has a shape which isobtained by uniting a lower part which is in a form of a circulartruncated cone whose bottom surface is the opposing surface 91 a andwhose horizontal cross section is progressively smaller toward above andan upper part which is in a form of a circular cylinder whose horizontalcross section is the top surface of the circular truncated cone. To bemore specific, a bottom rim portion of the atmosphere blocker plate 91is a slant 91 b which is inclined closer to the vertical axis J towardabove at the entire circumference. The top rim of the atmosphere blockerplate 91, namely, the section over the slant 91 b is a side surface 91 cwhich is approximately upright.

A processing liquid nozzle 8 is capable of selectively supplying at thebottom end the chemical solution or the rinsing liquid. Further, theprocessing liquid nozzle 8 is connected to a nozzle move mechanism notshown, and therefore, when driven by the nozzle move mechanism, theprocessing liquid nozzle 8 is positioned either to a close position (theposition shown in FIG. 11) which is close to the side surface 91 c ofthe atmosphere blocker plate 91 or to a retract position which is off tothe side (or to above) from the atmosphere blocker plate 91. Theprocessing liquid nozzle 8 is shaped like a cylindrical columnelongating vertically for instance so that a side surface of theprocessing liquid nozzle 8 is parallel to the side surface 91 c of theatmosphere blocker plate 91. Hence, when the nozzle 8 is positioned atthe close position, it is possible to eject the processing liquid towardthe slant 91 b.

While the opposing surface 91 a of the atmosphere blocker plate 91 is ahydrophobic surface which exhibits a hydrophobic property, the slant 91b is a hydrophilic surface which exhibits a hydrophilic property.Therefore, the processing liquid supplied to the slant 91 b flows downalong the slant 91 b. The processing liquid reaching the bottom end ofthe slant 91 b flows down to the top rim portion of the substrate Wwithout circulating onto the opposing surface 91 a which is ahydrophobic surface. To be more specific, the processing liquid flowingdown from the atmosphere blocker plate 91 is supplied to the topprocessing area TR which is on the outer side relative to the cross-linewith the top surface of the substrate W which is defined when the slant91 b is extended toward the substrate W, flows toward the rim of thesubstrate W under the centrifugal force which is created as thesubstrate W rotates, and flows down along the edge surface of thesubstrate W. Hence, as the substrate W rotates while the processingliquid is ejected at the processing liquid nozzle 8, the top rim portionof the substrate W is processed uniformly at the entire circumference.

An operation of the substrate processing apparatus having the structureabove will now be described with reference to FIG. 12. FIG. 12 is a flowchart of the operation of the substrate processing apparatus shown inFIG. 10. As the substrate W is mounted at its back surface on thesupports 7 with the device-seating surface of the substrate W facing up,the controller 80 moves down the atmosphere blocker plate 91 and theatmosphere blocker plate 91 is accordingly located close to thesubstrate W (Step S21). The inert gas is ejected at the plurality of gasejection outlets 9 b and the inert gas is supplied toward a centralportion of the top surface of the substrate W via the gas supply path18, whereby the substrate W is pressed against the supports 7 and heldat the spin base 5 (Step S22).

Next, the controller 80 activates the nozzle move mechanism and theprocessing liquid nozzle 8 accordingly is positioned at the closeposition which is close to the side surface 91 c of the atmosphereblocker plate 91 (Step S23). Following this, the motor 3 is driven andthe substrate W rotates (Step S24), and the motor 9 m of the block drivemechanism is driven and the atmosphere blocker plate 91 rotates aboutthe vertical axis J in the same direction at the approximately samenumber of revolutions as the spin base 5 (Step S25). The chemicalsolution is then supplied at the processing liquid nozzle 8 to the slant91 b of the atmosphere blocker plate 91. Thus supplied chemical solutionflows down the slant 91 b and reaches the top rim portion TR of therotating substrate W, which attains uniform chemical processing allaround the circumference of the substrate W over a predetermined widthfrom the end of the substrate W (Step S26).

The chemical solution will not circle over to the opposing surface 91 asince the opposing surface 91 a of the atmosphere blocker plate 91 is ahydrophobic surface, and the chemical atmosphere will not enter thenon-processing area NTR in a central portion of the top surface sincethe inert gas supplied into the space SP which is created between theatmosphere blocker plate 91 and the top surface of the substrate W flowsout along the diameter direction. Further, as the substrate W and theatmosphere blocker plate 91 rotate in synchronization, creation ofexcessive air flows is prevented, which prevent the chemical solutionfrom entering the non-processing area NTR owing to sucking in or jumpingof the chemical atmosphere around the substrate.

The chemical solution is then supplied also at the lower clean nozzle 41simultaneously with or after the supply of the chemical solution to thetop surface of the substrate W, thus achieving the chemical processingof the entire bottom surface of the substrate W (Step S27). After thechemical processing of the top rim portion TR and the bottom surface ofthe substrate W for a predetermined period of time, the supply of thechemical solution is stopped, and the chemical solution is drained offand discharged to outside the substrate. After draining off of thechemical solution, the rinsing liquid is supplied at the processingliquid nozzle 8 to the top rim portion of the substrate W (Step S28).The rinsing liquid thus washes away the chemical solution adhering tothe top rim portion TR of the substrate W. Alternatively, the rinsingliquid may be supplied also at the lower clean nozzle 41 simultaneouslywith or after the supply of the rinsing liquid to the top surface of thesubstrate W to thereby rinse the entire bottom surface of the substrateW (Step S29).

After the rinsing liquid is supplied to the top rim portion TR of thesubstrate W, the controller 80 drives the nozzle move mechanism and theprocessing liquid nozzle 8 is accordingly positioned to the retractposition (Step S30). Following this, the controller 80 allows supply ofthe inert gas into the space SP which is created between the top surfaceof the substrate W and the opposing surface 9 a of the atmosphereblocker plate 91, and opens the on-off valve 49, thereby introducing theinert gas into the space between the bottom surface of the substrate Wand the opposing surface of the spin base 5 at a predetermined flow ratefrom the gas supply path 48. The motor 3 and the motor 9 m of the blockdrive mechanism then rotate at a high speed, so that the liquidcomponents adhering to the substrate W and the atmosphere blocker plate91 are drained off owing to the centrifugal force and the substrate Wand the atmosphere blocker plate 91 are dried (Step S31).

After the drying of the substrate W ends, the controller 80 controls themotor 9 m, thereby stopping the rotations of the atmosphere blockerplate 91 (Step S32), and the controller 80 controls the motor 3, therebystopping the rotations of the substrate W (Step S33). The on-off valves19 and 23 are thereafter closed, the supply of the gas into the space SPis stopped, and the substrate W is accordingly released from pressingand holding (Step S34). The atmosphere blocker plate 91 then movestoward above, and the processed substrate W is unloaded.

As described above, this embodiment does not need a holding member suchas a chuck pin which contacts the outer edge of the substrate W andholds the substrate W, and therefore, effectively prevents re-adheringof the processing liquid to the surface of the substrate as in the caseof the earlier embodiments. Further, since the processing liquidsupplied at the processing liquid nozzle 8 and flowing down the slant 91b of the atmosphere blocker plate 91 is supplied to the top rim portion(top processing area) TR of the substrate W, the processing width isuniform all around the circumference of the substrate W. That is, theprocessing liquid flows down the slant 91 b of the atmosphere blockerplate 91 which is a hydrophilic surface and covers a certain range fromthe edge surface of the substrate W but will not circle over onto theopposing surface 91 a which is a hydrophobic surface, the processingwidth will not vary. Further, since the processing liquid can besupplied to the top rim portion TR of the substrate W while thesubstrate W as well as the atmosphere blocker plate 91 rotate, it ispossible to effectively prevent sucking in or jumping of the processingliquid back onto the central portion of the top surface (thenon-processing area NTR).

The invention is not limited to the embodiments described above but maybe modified in various manners in addition to the embodiments above, tothe extent not deviating from the object of the invention. For instance,although the embodiments described above are directed to the applicationof the invention to a substrate processing apparatus which cleans thebottom surface, the edge surface and the top rim portion of thesubstrate W, this is not limiting. For example, the invention isgenerally applicable to any substrate processing apparatus whichperforms processing such as cleaning, etching and developing to both thetop and the bottom surfaces of a substrate or only one of the bothsurfaces while rotating the substrate W.

Further, although the supports 7 are formed in the protrusions 5 a whichare obtained by locally protruding the rim portion of the spin base 5toward above in the embodiments described above, instead of protrudinglocal sections of the spin base 5 toward above, the supports 7themselves may be protruded toward above from the top surface of thespin base 5. Alternatively, the supports 7 may be buried inside the topsurface of the spin base 5 without protruding local sections of the spinbase 5 toward above and only the film members 71 may be protruded towardabove from the top surface of the spin base 5.

Further, although the gas ejection outlets 9 b are formed in theopposing surface 9 a of the atmosphere blocker plate 9 or 90 so as tovertically eject the inert gas on the rotation track Ta of the supports7 in the embodiments described above, this is not limiting. For example,the gas ejection outlets 9 b may be formed on the inner side relative tothe rotation track Ta of the supports 7 and the inert gas mayaccordingly be ejected downward and outward onto the rotation track Taof the supports 7.

Further, although the processing liquid nozzle 6 slides into the dent 90a which is at the rim of the atmosphere blocker plate 90 and ispositioned facing the top rim portion (top processing area) TR of thesubstrate W in the second embodiment described earlier, this is notlimiting. For example, as shown in FIGS. 13A and 13B, a through hole 9 ewhich is open vertically and accepts the processing liquid nozzle 6 maybe formed in the rim portion of the atmosphere blocker plate 90 and theprocessing liquid nozzle 6 may be inserted in the through hole 9 e untilthe bottom end of the processing liquid nozzle 6 becomes flush with theopposing surface 9 a to thereby position the processing liquid nozzle 6facing the top rim portion TR (FIG. 13A). In addition, when a gasintroduction inlet 9 d communicating with the gas distributing space 90c is formed in the inner wall of the through hole 9 e, as the processingliquid nozzle 6 retracts out from the through hole 9 e, the inert gasgets ejected out through both the top and the bottom openings of thethrough hole 9 e (FIG. 13B).

In this structure, as the nozzle 6 retracts out from the through hole 9e, the atmosphere blocker plate 90 rotates together with the substrateW. It is therefore possible to drain off the processing liquid adheringto the atmosphere blocker plate 90 and prevent rotation-induced creationof excessive air flows between the substrate W and the atmosphereblocker plate 90. This prevents sucking in of the chemical atmosphere orjumping of the chemical solution back into the space SP which is betweenthe substrate W and the atmosphere blocker plate 90.

Further, since the processing liquid nozzle 6 is in the through hole 9 ewhile the processing liquid is supplied, even if the processing liquidsplashes back toward the processing liquid nozzle 6 during processing ofthe substrate, the opposing surface 9 a of the atmosphere blocker plate90 blocks the processing liquid, preventing a large amount of theprocessing liquid from adhering to the nozzle 6. Hence, the processingliquid will not drop down from the nozzle 6 or adhere to the substrate Wor portions around the substrate W as the nozzle moves, which preventsthe processing liquid from exerting an adverse influence. The nozzle 6therefore does not have to be cleaned, which improves the throughput ofthe apparatus.

Further, since the inert gas is ejected through both the top and thebottom openings of the through hole 9 e even when the nozzle 6 retractsaway from the atmosphere blocker plate 90 in this embodiment, theprocessing liquid will not enter the through hole 9 e or jump back ontothe substrate W. It is thus possible to prevent corrosion of thedevice-seating surface which is in the central portion of the topsurface (the non-processing area NTR) of the substrate W.

The present invention is applicable to a substrate processing apparatuswhich performs processing such as cleaning to the surfaces of substratesin general including semiconductor wafers, glass substrates forphotomask, glass substrates for liquid crystal display, glass substratesfor plasma display and optical disk substrates.

Although the invention has been described with reference to specificembodiments, this description is not meant to be construed in a limitingsense. Various modifications of the disclosed embodiment, as well asother embodiments of the present invention, will become apparent topersons skilled in the art upon reference to the description of theinvention. It is therefore contemplated that the appended claims willcover any such modifications or embodiments as fall within the truescope of the invention.

1. A substrate processing apparatus which performs predeterminedprocessing by supplying a processing liquid to a substrate whilerotating said substrate, comprising: a rotary member which is structuredto rotate freely about a vertical axis; a rotating element which rotatessaid rotary member; a support element which is disposed upward to saidrotary member and which comprises at least three supporting memberswhich abut on a bottom surface of said substrate to thereby support saidsubstrate with a distance from said rotary member; and a pressingelement which presses said substrate against said supporting members bysupplying gas to a top surface of said substrate and accordingly makessaid rotary member hold said substrate.
 2. The substrate processingapparatus of claim 1, further comprising a driver which applies driveforce to said support element, wherein said support element comprises,as said supporting members, at least four movable members which arestructured to freely move away from and abut on the bottom surface ofsaid substrate, said processing is executed by supplying said processingliquid to the bottom surface of said substrate while said movablemembers of at least three abut on the bottom surface of said substrateto support said substrate under the drive force from said driver, andsaid driver makes each one of said movable members move away from thebottom surface of said substrate at least once during said processing.3. The substrate processing apparatus of claim 1, wherein said pressingelement comprises: a platy member which has an opposing surface whichopposes against the top surface of said substrate and in which a gasejection outlet is formed, and a gas supplying part which guides andsupplies gas to a space which is created between said opposing surfaceand the top surface of said substrate by ejecting gas at the gasejection outlet.
 4. The substrate processing apparatus of claim 3,wherein said gas ejection outlet in said opposing surface is formed on arotation track of said supporting members and ejects gas in asubstantially vertical direction, thereby pressing said substrateagainst said supporting members.
 5. The substrate processing apparatusof claim 3, wherein said platy member is structured to be able to rotateabout said vertical axis, and said rotating element rotates said platymember together with said substrate while said pressing element makessaid rotary member hold said substrate.
 6. The substrate processingapparatus of claim 1, further comprising a bottom-side processing liquidsupplier which supplies said processing liquid toward the bottom surfaceof said substrate which rotates as it is pressed against said supportingmembers, wherein said pressing element supplies gas to a non-processingarea which is on an inner side relative to a top processing area whichis processed with said processing liquid supplied by said bottom-sideprocessing liquid supplier to the bottom surface of said substrate andcircling over to a rim portion of the top surface of said substrate, andsaid supporting members abut on the bottom surface of said substratecorresponding to said non-processing area and accordingly support saidsubstrate.
 7. The substrate processing apparatus of claim 1, furthercomprising a top-side processing liquid supplier which supplies saidprocessing liquid to a rim portion of the top surface of said substratewhich rotates as it is pressed against said supporting members.
 8. Asubstrate processing method in which predetermined processing isperformed by supplying a processing liquid to a substrate while rotatingsaid substrate, said method comprising steps of: making at least threesupporting members which are disposed upward to a rotary member abut ona bottom surface of said substrate to thereby support said substratewith a distance from said rotary member; pressing said substrate againstsaid supporting members by supplying gas to a top surface of saidsubstrate and accordingly makes said rotary member hold said substrate;and rotating said rotary member about a vertical axis to therebyrotating said substrate.